Superabsorbent Polymer based Biosensor Apparatus and Methods

Abstract

The invention relates to an absorbent sensing material for interrogation of sample liquid to detect analyte, comprising: dry superabsorbent polymer (SAP) configured to receive a sample liquid; the absorbent material comprising, within the dry superabsorbent polymer, at least one dry reaction component for detecting and for signalling the presence of 5 analyte; wherein, upon insult of sample liquid, the dry superabsorbent polymer absorbs sample liquid, the at least one dry reaction component dissolves and, if analyte is present in the sample liquid, its presence is detected and signalled. The invention also relates to use of the absorbent sensing material, absorbent articles and methods of manufactures of absorbent articles and test sensors such as test strips.

1 . An absorbent sensing material for interrogation of sample liquid to detect analyte,
 comprising:   a modified dry superabsorbent polymer (SAP) configured to receive a sample liquid;   the modified dry superabsorbent polymer comprising a dry superabsorbent polymer and at least one dry reaction component for detecting and for signalling the presence of analyte;   wherein, upon insult of sample liquid, the modified dry superabsorbent polymer absorbs sample liquid, the at least one dry reaction component dissolves and, if analyte is present in the sample liquid, its presence is detected and signalled.   
     
     
         2 . An absorbent sensing material according to  claim 1  comprising: at least 50%, or at least 75%, or at least 90%, or at least 95%, by weight of modified dry superabsorbent polymer comprising the at least one dry reaction component. 
     
     
         3 . An absorbent sensing material according to  claim 1  in which the modified dry superabsorbent polymer material comprises at least 95% by weight, or at least 97% by weight of dry superabsorbent polymer and up to 5% by weight, or up to 3% by weight, of the at least one dry reaction component(s). 
     
     
         4 . An absorbent sensing material according to  claim 1  in which modified dry superabsorbent polymer is configured to receive a discrete amount of a sample liquid. 
     
     
         5 . An absorbent sensing material according to  claim 1  in which the modified dry superabsorbent polymer provides a sample chamber of at least one of: limited mass, limited volume. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . An absorbent sensing material according to any of  claim 1  in which the modified dry superabsorbent polymer comprises particles. 
     
     
         10 . (canceled) 
     
     
         11 . An absorbent sensing material according to  claim 9  in which at least 90% by weight of the particles are within a range selected from one of the following: ≤±10%≤±5%≤±2% of the 0 dry weight of the particles. 
     
     
         12 . An absorbent sensing material according to  claim 9  in which the particles are within a range of ≤+/−10% the average size particles. 
     
     
         13 . An absorbent sensing material according to  claim 12  in which, when dry, the particles have a main dimension selected from of: ≤100 nanometres, 100 to 1000 nanometres, 100 to 5000 nanometres, 5 to 1000 microns, 5 to 500 microns, 5 to 250 microns, 500 microns, ≤0.1 mm, 0.05 mm, ≤0.01 mm≤0.005 mm 0.5 to 5 mm, from 1 mm to 4 mm, from 0.5 mm to 3 mm, from 0.5 mm to 2 mm, from 1 mm to 2 mm. 
     
     
         14 . An absorbent sensing material according to  claim 1  in which the at least one dry reaction component comprises:
 at least one dry transducing component for detecting an analyte; 
 and, 
 at least one dry signalling component responsive to the detection of analyte for signalling the presence of analyte. 
 
     
     
         15 . An absorbent sensing material according to  claim 1  in which the at least one reaction component comprises at least one of
 an electrochemical assay; 
 a colorimetric assay; 
 a nitrate assay; 
 a ketone assay; 
 a glucose assay; 
 a bilirubin assay; 
 a component capable of photometric detection; 
 a component capable of spectrometric detection. 
 
     
     
         16 . An absorbent sensing material according to  claim 1  in which the at least one reaction component comprises a colorimetric assay comprising a chromogen. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . An absorbent sensing material according to  claim 1  in which the modified dry superabsorbent polymer comprises at least 50% or at least 75% or at least 90% by weight of at least one of:
 polymerised acrylic acid, salts of polymerised acrylic acid, sodium polyacrylate, polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile. 
 
     
     
         20 . An absorbent sensing material according to  claim 19  in which the superabsorbent polymer comprises at least 50% or at least 75% or at least 90% by weight of at least one of: polymerised acrylic acid or salts thereof, sodium polyacrylate, polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile. 
     
     
         21 . A disposable absorbent article for sample fluid interrogation comprising an absorbent core, at least a portion of the absorbent core comprising absorbent sensing material for interrogation of sample liquid to detect analyte, the absorbent sensing material comprising:
 a modified dry superabsorbent polymer (SAP) configured to receive a sample liquid;   the modified dry superabsorbent polymer comprising a dry superabsorbent polymer and at least one dry reaction component for detecting and for signalling the presence of analyte;   wherein, upon insult of sample liquid, the modified dry superabsorbent polymer absorbs sample liquid, the at least one dry reaction component dissolves and, if analyte is present in the sample liquid, its presence is detected and signalled.   
     
     
         22 . A disposable absorbent article according to  claim 21  in which at least a portion of the modified dry superabsorbent polymer of the absorbent material comprises at least one of: superabsorbent polymer particles, superabsorbent polymer fibres. 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . A disposable absorbent article according to  claim 21  in which the absorbent sensing material is provided within a compartment of limited volume, having at least one impervious wall to resist further ingress of sample liquid once full. 
     
     
         26 . A disposable absorbent article according to  claim 21  in which at least two groups of modified dry superabsorbent polymer particles are provided, at least one group configured to be indicative of a first level of analyte, and a second group configured to be indicative of a second level of analyte. 
     
     
         27 . Use of an absorbent sensing material according to  claim 1  for detecting and for signalling the presence of one or more analytes in a sample liquid—in which the modified dry superabsorbent polymer is used as a sample chamber to absorb a predetermined amount of the at least one reaction component. 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . A method of manufacturing an absorbent sensing material for interrogation of sample liquid to detect analyte, the absorbent sensing material comprising: a modified dry superabsorbent polymer configured to receive a sample liquid; the modified dry superabsorbent polymer comprising a dry superabsorbent polymer and at least one dry reaction component for detecting and for signalling the presence of analyte; wherein, upon insult of sample liquid, the modified dry superabsorbent polymer absorbs sample liquid, the at least one dry reaction component dissolves and, if analyte is present in the sample liquid, its presence is detected and signalled, the method comprising:
 a. preparing superabsorbent polymer particles;   b. drying the superabsorbent polymer particles;   c. in the absence of an analyte, introducing at least one wet reaction component for detecting and signalling the presence of the analyte, to the dry superabsorbent polymer particles;   d. drying the modified superabsorbent polymer particles to form modified dry superabsorbent polymer particles pre-loaded with the at least one dry reaction component for detecting and signalling the presence of an analyte.   
     
     
         31 . (canceled) 
     
     
         32 . A process for detecting analyte in a fluid comprising:
 a) providing absorbent sensing material according for interrogation of sample liquid to detect analyte, the absorbent sensing material comprising: a modified dry superabsorbent polymer (SAP) configured to receive a sample liquid; the modified dry superabsorbent polymer comprising a dry superabsorbent polymer and at least one dry reaction component for detecting and for signalling the presence of analyte; wherein, upon insult of sample liquid, the modified dry superabsorbent polymer absorbs sample liquid, the at least one dry reaction component dissolves and, if analyte is present in the sample liquid, its presence is detected and signalled;   b) insulting the absorbent sensing material comprising modified dry superabsorbent polymer, with sample liquid   c) optionally, re-insulting the absorbent sensing material with sample liquid;   d) at least partially rehydrating the modified dry superabsorbent polymer;   e) at least partially rehydrating the at least one reaction component to detect and signal the presence and/or concentration of analyte in the sample liquid;   f) detecting and signalling the presence of analyte in the sample liquid.   
     
     
         33 . An absorbent material to  claim 1  in which at least two groups of modified dry superabsorbent polymer particles are provided, at least one group configured to be indicative of a first level of analyte, and a second group configured to be indicative of a second level of analyte.